Curl an image from a container field

Hiya,

I am trying to upload an image using Smartpill and cURL to my webservice.

The following code works well to grab an image from a URL and then upload it to my webservice. My problem however is how to get the image from a container field instead of a URL. I think it is only grabbing the name of the image, not the actual file itself?

I am using Windows. Can anyone help?

$url = 'http://sprott.physics.wisc.edu/fractals/carlson/PGPHX82.GIF';

$datain = file_get_contents($url);

$ctype= "image/gif";



$ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, "https://garytest.nordic-e.com/__API__/picture/8/data");

    curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY);

    curl_setopt($ch, CURLOPT_USERPWD,"testuser:testpass");

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);

    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);

    curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');

    curl_setopt($ch, CURLOPT_HTTPHEADER, array("Content-Type" => $ctype));

    

curl_setopt($ch, CURLOPT_POSTFIELDS, $datain);



    $data = curl_exec($ch);

    print curl_error($ch);

echo $data;

    curl_close($ch);